Investigation into Corrosive Wear of the CoCrFeNiTax Laser-Clad Coatings on TC4 in the Neutral and Alkaline Circumstance

Abstract

CoCrFeNiTax (x = 0, 1) coatings were prepared on the surface of TC4 by laser-cladding to improve the corrosive wear property of TC4 and extend its service life in corrosive media, ultimately aiming to improve its surface performance. The effects of Ta addition on the phase constituent and microstructure of the coatings were first investigated. Given the wide application of TC4 in corrosive media (even undergoing friction), the corrosive wear of TC4 covered with the coatings was especially focused in two media (neutral and alkaline). The results showed that the coatings were composed of primary α(Ti) and eutecticum (α(Ti) + Ti2Ni) as the matrix and TiC as the reinforcement. The introduction of Ta increased the volume fraction of eutecticum and TiC and made the microstructure more uniform. The coating with Ta performed more outstanding corrosive wear resistance than the other two samples in the two media. The wear rate of the coating with Ta was 4.7458 × 10−4 mm3·N−1·m−1 in the neutral environment and 6.6808 × 10−4 mm3·N−1·m−1 in the alkaline environment, 64.45% and 61.79% lower than those of TC4, respectively. The wear mechanism of the samples is a combination of serious micro-cutting, active dissolution, and oxidation, and the introduction of Ta effectively improved the resistance to micro-cutting.